Don't mind!
I get the similar messages since many weeks, I can login anyway.

Benjamin of Rivendell, son of David of Rivendell, grandson of Delia of Rivendell, great-grandson of Ricarda of Rivendell, great-great-grandson of Mary of Rivendell, called "Mary Gold" because of her golden hair

If you sent or receive data from an https is encrypted, therefor a certificate is required. The lifetime of these certificates is limited, the one of KH ended december 18th 2014.
It still works! But since its lifetime is over your browser isn't sure wether it can trust it or not. And whenever a machine doesn't know what to do it is asking the one in front of the screen

Benjamin of Rivendell, son of David of Rivendell, grandson of Delia of Rivendell, great-grandson of Ricarda of Rivendell, great-great-grandson of Mary of Rivendell, called "Mary Gold" because of her golden hair